Area Forecast Discussion

WHAT HAS CHANGED

Aviation Updated for 12 UTC.

Frost Advisory has been issued for much of SE West Virginia and a Freeze Warning has been issued for Western Greenbrier county for Sunday night into Monday morning.

Wind Advisory remains in effect Sunday from 6am til 4pm for the southern Blue Ridge from Floyd County, VA to Watauga County, NC, for gusts 45-50 mph.

KEY MESSAGES

1. Limited chances for mountain showers through the weekend. Better chances for more widespread rainfall next weekend.

2. Strong post-frontal winds Sunday with gusts 45 to 50 mph along the southern Blue Ridge.

3. Cooler Sunday behind the front, with frost/freeze possible tonight, but especially Monday night, then warming up mid to late week.

DISCUSSION

KEY MESSAGE 1: Limited chances for mountain showers through the weekend. Better chances for more widespread rainfall next weekend.

Behind the frontal passage today, surface high pressure will quickly build in, bringing an end to any lingering rainfall. Consensus among short range models is for rain to continue east into the Piedmont, and for shower coverage to increase as the front nears eastern VA. Rainfall amounts thus have trended slightly up for parts of the central VA Piedmont, but closer to two tenths of an inch. So, while a little bit more rain may come, it will still not bring much improvement to the ongoing drought in those areas.

A secondary front reaches the far northwestern parts of the forecast area late tonight, and with colder air in place, could see some snow flurries in parts of the southeast WV mountains, though accumulations will be light, if any, given how warm ground temperatures have been.

Beyond that secondary front, a broad area of surface high pressure expands over most of the eastern US, and 500mb flow turns northwesterly as the trough departs to the east, and dry weather will ensue for the first half of the work week. By midweek, another front drops southward towards the area, but shower and thunderstorm chances appear limited to the northern half of the forecast area at this time, so north of the New River Valley. NBM probability for 24hr rainfall amounts at least 0.10" through Thursday morning are between 10% and 30% north of US 460 to the northern border of the CWA. South of US 460 has less than a 10% chance to see that much rain.

However, another, stronger front approaches the area from the west by the weekend. The surface high moves offshore, and surface flow turns more southwesterly, so can tap into some moisture from the Gulf and from the Atlantic. Does not look to be anonymously high moisture, PWATs are briefly near the 90th percentile relative to climatology early Saturday, but at least looks to be more moisture than this region has seen received, with forecast soundings showing PWATs near 1.25". NBM probs for a tenth of an inch of rain through Sunday morning are over 55% areawide, and between 40% to 50% for 0.25" inches of rain across the area.

KEY MESSAGE 2: Post-frontal winds gusting 35 to 50 mph, wind advisory southern Blue Ridge Sunday starting at 6am.

Models showing decent pressure rises behind the front with strong cold advection. Coupled with a 45kt jet, appears our southern Blue Ridge could have gusts 45-50 mph from Floyd to Watauga starting around dawn Sunday then leveling off by early afternoon.

Key Message 3: Cooler Sunday behind the front, with frost/freeze possible tonight, but especially Monday night, then warming up mid to late week.

Cooler temperatures advecting into the region behind the cold front today and through the overnight hours tonight will lead to the possibility of frost and freeze conditions across portions of SE West Virginia tonight. Some patchy frost can't be ruled out across portions of SW Virginia. While frost development potential is on the lower side tonight given elevated winds and lower RH values, sheltered locations may develop isolated patches of frost tonight across the regions mentioned above. Given this potential, a Frost Advisory has been issued for much of SE West Virginia, and a Freeze Warning has been issued for western Greenbrier county, where temperatures look to dip below freezing tonight.

Additional frost and freeze headlines may be necessary Monday night into Tuesday as surface high pressure settles over the region leading to clear skies and calm winds. Low temperatures Monday night look to dip to near or below freezing for the entire region.

Warmer temperatures return Tuesday as the upper level ridge builds back into the region.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Scattered showers along a passing cold front will bring periodic MVFR CIGs and VSBYs to mountain terminals through the remainder of the early morning hours. MVFR CIGs look to linger at all mountain terminals through at least the 15-18 UTC timeframe today, before westerly/northwesterly winds advect drier air into the region. This will return VFR conditions back into the region by 18 UTC for all terminals. Occasional sub-VFR is possible at ROA and LYH/DAN periodically this morning.

Winds have already started to shift to out of the west/northwest, and will continue to do so through the remainder of the early morning hours. by 12 UTC, wind gusts of 20-35kts are likely at ROA/BCB/BLF, and LWB. These gusts will slide east through the morning hours to LYH and DAN; however, look to remain in the 20-25kt range. Gusts look to diminish towards 00 UTC Monday as gradient winds start to calm across the region.

EXTENDED AVIATION OUTLOOK...

A secondary front enters the area Monday and could bring near sub-VFR at LWB/BLF Sunday night-Monday morning but in general VFR is expected through the week.

FIRE WEATHER

Strong west to northwest winds should dry fuels efficiently Sunday afternoon, though temps will be cooler than today. Still RH dropping to as low as 15 to 25 percent will lead to quick drying of fine fuels today.

Monday appears just as dry and with another day of drying could be a day where wildfire spread is higher with RH values again dropping into the teens along/east of the Blue Ridge and 20-27 percent in the mountains.

The rest of the week appears mostly dry, with temps warming up after Tuesday back to above normal values.

The next widespread rain chances won't return to the area until next Saturday/Sunday.

RNK WATCHES / WARNINGS / ADVISORIES

VA...Wind Advisory until 4 PM EDT this afternoon for VAZ015>017. NC...Wind Advisory until 4 PM EDT this afternoon for NCZ001-002-018. WV...Frost Advisory from 2 AM to 10 AM EDT Monday for WVZ042>044- 507. Freeze Warning from 2 AM to 10 AM EDT Monday for WVZ508.